Solar cells have been extensively investigated for many years, with a major emphasis on increasing efficiency and reducing cost. One approach that has been considered for improving solar cell performance is the use of nano-structuring in solar cells. Examples include the nano-coax structures of U.S. Pat. No. 7,754,964 and the nano-pillars and nano-cones of US 2010/0240167. However, there are aspects of nano-structured solar cells that do not appear to have been appreciated in the art.